System for pumping hydraulic fracturing fluid using electric pumps

Abstract

A system for hydraulically fracturing an underground formation in an oil or gas well to extract oil or gas from the formation, the oil or gas well having a wellbore that permits passage of fluid from the wellbore into the formation. The system includes a plurality of pumps powered by electric induction motors and fluidly connected to the well, the pumps configured to pump fluid into the wellbore at high pressure so that the fluid passes from the wellbore into the, and fractures the formation. The system can also include a plurality of natural gas powered generators electrically connected to the plurality of pumps to provide electrical power to the pumps.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of, and claims priority to and the benefit of, U.S. patent application Ser. No. 13 / 679,689, which was filed Nov. 16, 2012, the full disclosure of which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This technology relates to hydraulic fracturing in oil and gas wells. In particular, this technology relates to pumping fracturing fluid into an oil or gas well using pumps powered by electric motors.[0004]2. Brief Description of Related Art[0005]Hydraulic fracturing has been used for decades to stimulate production from conventional oil and gas wells. The practice consists of pumping fluid into a wellbore at high pressure. Inside the wellbore, the fluid is forced into the formation being produced. When the fluid enters the formation, it fractures, or creates fissures, in the formation. Water, as well as other fluids, and some solid proppants, are t...

AI Technical Summary

Benefits of technology

The patent text describes a technical solution for preventing damage to electric motors that may occur due to grounding or short circuits. The solution involves performing diagnostics on the electric motor frequently using a variable frequency drive. The drive also includes power semiconductor heat sinks with thermal sensors that are monitored by a microprocessor. This helps to prevent damage to the semiconductor caused by excessive heat. Overall, this patent provides a way to protect electric motors from damage and improve their overall stability and reliability.

Problems solved by technology

Such pumps are able to pump fracturing fluid into a wellbore at a high enough pressure to crack the formation, but they also have drawbacks.

For example, the diesel pumps are very heavy, and thus must be moved on heavy duty trailers, making transport of the pumps between oilfield sites expensive and inefficient.

In addition, the diesel engines required to drive the pumps require a relatively high level of expensive maintenance.

Furthermore, the cost of diesel fuel is much higher than in the past, meaning that the cost of running the pumps has increased.

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